Came across this link, thought i would share. I think its a very clever idea to support your tomatos and have a nutrient delivery system all in one. May have to try this this year
DIY steps here
http://www.itsatormato.com./index.php?option=com_content&view=section&layout=blog&id=5&Itemid=53
DIY steps here
http://www.itsatormato.com./index.php?option=com_content&view=section&layout=blog&id=5&Itemid=53